[Extreme lateral lumbar intervertebral disk displacement. Incidence, symptoms and therapy].

Upper lumbar nerve root compression or a femoralgia is often caused by extreme lateral lumbar disc herniation. This type of lumbar disc herniation compresses the nerve root inside or laterally to the intervertebral canal, while mediolateral disc herniations squeeze it in the lateral recess. Pain radiating obliquely over the thigh is the dominant clinical symptom. Bending the body to the ipsilateral side usually increases the pain. When neurologic signs are present, motor deficits tend to be more prominent than sensory and the deficits never affect more than one nerve root. Most frequently a weakness of knee extension occurs.